1. Field of the Invention
The present invention relates to air cleaning systems for welding chambers. In particular, the present invention relates to an air cleaning system which provides a reduction in maintenance for cleaning the air flow path and filters of an air cleaning system and in some embodiments obviates the need for a spark arrestor.
2. Description of Related Art
Welding of metal parts and welding to build products is an inherently dangerous endeavor. Not only are the sparks and hot metal pieces easy to start fires, cause burns and the like, but the gases and dust created during the welding process can be toxic, as well as detrimental, to the product being produced. Generally, welding is carried out in a welding chamber which controls dust and particulate matter generated by the process of circulating and filtering the air that enters the welding chamber before returning it to the surrounding environment.
Older welding chamber air filtration systems consist of an air cleaning system which is positioned on the floor just outside the welding chamber, or outside the building the welding chamber is positioned in. They are connected to the air flow from the welding chamber by one or more air hoses. Not only does this older system waste valuable floor space, but use of ducting adds considerably to the maintenance and cleaning of a welding system. Further, ducts can collapse spilling their contents and causing an even further maintenance catastrophe.
A more recent approach to air handling systems for welding chambers which is superior in many ways to the side mounted units, has been the introduction of the overhead air cleaning system for welding stations. These air cleaning systems have the ability to be in direct connection with the interior of a chamber, eliminating the need for ducting, and also eliminate many of the other problems associated with side mounted air systems and lengthy ducted systems.
The air cleaning systems contain one of a variety of different types of air filtration devices. One cleaning filter method in addition to standard charcoal, HEPA and other filter units is the self cleaning pulsed air filter. These filters comprise a paper or cloth filter which air moves through trapping particles. At desired intervals, a pulse of reverse flow air is blown through the filter, releasing the trapped particles for collection below the filter. Typically, air cleaning systems provide a door which must be opened and a collector below the air filter also must be handled and cleaned. These work well, but expose the worker who cleans the unit to the filter and interior of the filter chamber every time the tray needs to be cleaned, exposing the worker and surrounding environment to a higher level of contaminants. In U.S. Pat. No. 4,359,330 issued Nov. 16, 1982 to Copley, there is disclosed a self cleaning pulsed air cleaner designed for use in air cleaning systems. The system describes methods for preventing the recontamination of the air filter after it has been pulsed but, nothing to prevent exposure to the filter every time the collection tray is cleaned.
In addition to a wide variety of filters there are several different approaches to the air cleaning system. In U.S. Pat. No. 6,036,736 issued Mar. 14, 2000 to Wallace, et al., there is disclosed a ventilating method wherein an air blower, suitable for fumes filtering by a contaminate filter, a charcoal filter and a HEPA filter is disclosed. The device is mounted on top of a framed box and includes spark arrestor means. In U.S. Pat. No. 4,606,260 issued Aug. 19, 1986 to Cox, there is disclosed a movable welding station with a top frame mounted exhaust hood, including charcoal filters. In U.S. Pat. No. 6,758,875 issued Jul. 6, 2004 to Reid et al., there is disclosed a top frame mounted air cleaning system. The system includes a blower housing, frame, filters, shields and a spark arrestor. This particular air cleaning system has a framing system for supporting the air cleaning on top of the cabinet. The support consists of corner posts with a top corner to corner cross member of long, heavy, metal “beams”. The beams are indicated as relatively tall and in some embodiments must be further supported by cross posts (i.e. cross members like the upright posts which add support to the heavy beams of the invention, FIGS. 1 and 2). Upright posts and cross beams are a fairly standard construction method for framing systems in general and as with any older technology, present a variety of problems including their size and greater weight.
While all the above overhead air cleaning system inventions include spark arrestors and cleaning filters, their close positioning to the welding activity cause increased problems with filter replacement, cleaning and spark problems including catastrophic fires. In addition, heavy, thick or large cross beams are more expensive, have weight related problems, are harder to work with and still need in some cases, further support to work with heavy air blower units, filters must be replaced fairly frequently, sparks start fires and the labor to shut down and clean the devices and filters becomes more costly than non top mounted devices. Even with top mounted devices cleaning of filters becomes a problem and when the air cleaning system must be cleaned, that is valuable time that the welding system cannot be used for its intended purpose.
The problems of the present state of the art would be greatly reduced with new methods and devices that reduce the frequency of cleaning, improve the ease of cleaning, reduce the possibility of spark initiated fires and provide better designed framing to support top mounted air handling systems for welding booths.